2.4/user/javadoc/com/google/gwt/examples/cellview/CellTreeExample2.java - gwt - Git at Google

 /*
  * Copyright 2010 Google Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License"); you may not
  * use this file except in compliance with the License. You may obtain a copy of
  * the License at
  *
  * http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  * License for the specific language governing permissions and limitations under
  * the License.
  */
 package com.google.gwt.examples.cellview;

 import com.google.gwt.cell.client.AbstractCell;
 import com.google.gwt.cell.client.Cell;
 import com.google.gwt.cell.client.TextCell;
 import com.google.gwt.core.client.EntryPoint;
 import com.google.gwt.safehtml.shared.SafeHtmlBuilder;
 import com.google.gwt.user.cellview.client.CellTree;
 import com.google.gwt.user.cellview.client.HasKeyboardSelectionPolicy.KeyboardSelectionPolicy;
 import com.google.gwt.user.cellview.client.TreeNode;
 import com.google.gwt.user.client.ui.RootLayoutPanel;
 import com.google.gwt.view.client.ListDataProvider;
 import com.google.gwt.view.client.SingleSelectionModel;
 import com.google.gwt.view.client.TreeViewModel;

 import java.util.ArrayList;
 import java.util.List;

 /**
  * Example of {@link CellTree}. This example shows a Tree consisting of
  * composers and the compositions they created.
  */
 public class CellTreeExample2 implements EntryPoint {

   /**
    * A list of songs.
    */
   private static class Playlist {
     private final String name;
     private final List<String> songs = new ArrayList<String>();

     public Playlist(String name) {
       this.name = name;
     }

     /**
      * Add a song to the playlist.
      *
      * @param name the name of the song
      */
     public void addSong(String name) {
       songs.add(name);
     }

     public String getName() {
       return name;
     }

     /**
      * Return the list of songs in the playlist.
      */
     public List<String> getSongs() {
       return songs;
     }
   }

   /**
    * A composer of classical music.
    */
   private static class Composer {
     private final String name;
     private final List<Playlist> playlists = new ArrayList<Playlist>();

     public Composer(String name) {
       this.name = name;
     }

     /**
      * Add a playlist to the composer.
      *
      * @param playlist the playlist to add
      */
     public Playlist addPlaylist(Playlist playlist) {
       playlists.add(playlist);
       return playlist;
     }

     public String getName() {
       return name;
     }

     /**
      * Return the rockin' playlist for this composer.
      */
     public List<Playlist> getPlaylists() {
       return playlists;
     }
   }

   /**
    * The model that defines the nodes in the tree.
    */
   private static class CustomTreeModel implements TreeViewModel {

     private final List<Composer> composers;

     /**
      * This selection model is shared across all leaf nodes. A selection model
      * can also be shared across all nodes in the tree, or each set of child
      * nodes can have its own instance. This gives you flexibility to determine
      * how nodes are selected.
      */
     private final SingleSelectionModel<String> selectionModel = new SingleSelectionModel<String>();

     public CustomTreeModel() {
       // Create a database of information.
       composers = new ArrayList<Composer>();

       // Add compositions by Beethoven.
       {
         Composer beethoven = new Composer("Beethoven");
         composers.add(beethoven);

         Playlist concertos = beethoven.addPlaylist(new Playlist("Concertos"));
         concertos.addSong("No. 1 - C");
         concertos.addSong("No. 2 - B-Flat Major");
         concertos.addSong("No. 3 - C Minor");
         concertos.addSong("No. 4 - G Major");
         concertos.addSong("No. 5 - E-Flat Major");

         Playlist quartets = beethoven.addPlaylist(new Playlist("Quartets"));
         quartets.addSong("Six String Quartets");
         quartets.addSong("Three String Quartets");
         quartets.addSong("Grosse Fugue for String Quartets");

         Playlist sonatas = beethoven.addPlaylist(new Playlist("Sonatas"));
         sonatas.addSong("Sonata in A Minor");
         sonatas.addSong("Sonata in F Major");

         Playlist symphonies = beethoven.addPlaylist(new Playlist("Symphonies"));
         symphonies.addSong("No. 2 - D Major");
         symphonies.addSong("No. 2 - D Major");
         symphonies.addSong("No. 3 - E-Flat Major");
         symphonies.addSong("No. 4 - B-Flat Major");
         symphonies.addSong("No. 5 - C Minor");
         symphonies.addSong("No. 6 - F Major");
         symphonies.addSong("No. 7 - A Major");
         symphonies.addSong("No. 8 - F Major");
         symphonies.addSong("No. 9 - D Minor");
       }

       // Add compositions by Brahms.
       {
         Composer brahms = new Composer("Brahms");
         composers.add(brahms);
         Playlist concertos = brahms.addPlaylist(new Playlist("Concertos"));
         concertos.addSong("Violin Concerto");
         concertos.addSong("Double Concerto - A Minor");
         concertos.addSong("Piano Concerto No. 1 - D Minor");
         concertos.addSong("Piano Concerto No. 2 - B-Flat Major");

         Playlist quartets = brahms.addPlaylist(new Playlist("Quartets"));
         quartets.addSong("Piano Quartet No. 1 - G Minor");
         quartets.addSong("Piano Quartet No. 2 - A Major");
         quartets.addSong("Piano Quartet No. 3 - C Minor");
         quartets.addSong("String Quartet No. 3 - B-Flat Minor");

         Playlist sonatas = brahms.addPlaylist(new Playlist("Sonatas"));
         sonatas.addSong("Two Sonatas for Clarinet - F Minor");
         sonatas.addSong("Two Sonatas for Clarinet - E-Flat Major");

         Playlist symphonies = brahms.addPlaylist(new Playlist("Symphonies"));
         symphonies.addSong("No. 1 - C Minor");
         symphonies.addSong("No. 2 - D Minor");
         symphonies.addSong("No. 3 - F Major");
         symphonies.addSong("No. 4 - E Minor");
       }

       // Add compositions by Mozart.
       {
         Composer mozart = new Composer("Mozart");
         composers.add(mozart);
         Playlist concertos = mozart.addPlaylist(new Playlist("Concertos"));
         concertos.addSong("Piano Concerto No. 12");
         concertos.addSong("Piano Concerto No. 17");
         concertos.addSong("Clarinet Concerto");
         concertos.addSong("Violin Concerto No. 5");
         concertos.addSong("Violin Concerto No. 4");
       }
     }

     /**
      * Get the {@link NodeInfo} that provides the children of the specified
      * value.
      */
     public <T> NodeInfo<?> getNodeInfo(T value) {
       if (value == null) {
         // LEVEL 0.
         // We passed null as the root value. Return the composers.

         // Create a data provider that contains the list of composers.
         ListDataProvider<Composer> dataProvider = new ListDataProvider<CellTreeExample2.Composer>(
             composers);

         // Create a cell to display a composer.
         Cell<Composer> cell = new AbstractCell<Composer>() {
           @Override
           public void render(Context context, Composer value, SafeHtmlBuilder sb) {
             if (value != null) {
               sb.appendEscaped(value.getName());
             }
           }
         };

         // Return a node info that pairs the data provider and the cell.
         return new DefaultNodeInfo<Composer>(dataProvider, cell);
       } else if (value instanceof Composer) {
         // LEVEL 1.
         // We want the children of the composer. Return the playlists.
         ListDataProvider<Playlist> dataProvider = new ListDataProvider<Playlist>(
             ((Composer) value).getPlaylists());
         Cell<Playlist> cell = new AbstractCell<Playlist>() {
           @Override
           public void render(Context context, Playlist value, SafeHtmlBuilder sb) {
             if (value != null) {
               sb.appendEscaped(value.getName());
             }
           }
         };
         return new DefaultNodeInfo<Playlist>(dataProvider, cell);
       } else if (value instanceof Playlist) {
         // LEVEL 2 - LEAF.
         // We want the children of the playlist. Return the songs.
         ListDataProvider<String> dataProvider = new ListDataProvider<String>(
             ((Playlist) value).getSongs());

         // Use the shared selection model.
         return new DefaultNodeInfo<String>(dataProvider, new TextCell(),
             selectionModel, null);
       }

       return null;
     }

     /**
      * Check if the specified value represents a leaf node. Leaf nodes cannot be
      * opened.
      */
     public boolean isLeaf(Object value) {
       // The leaf nodes are the songs, which are Strings.
       if (value instanceof String) {
         return true;
       }
       return false;
     }

   }

   public void onModuleLoad() {
     // Create a model for the tree.
     TreeViewModel model = new CustomTreeModel();

     /*
      * Create the tree using the model. We use <code>null</code> as the default
      * value of the root node. The default value will be passed to
      * CustomTreeModel#getNodeInfo();
      */
     CellTree tree = new CellTree(model, null);
     tree.setKeyboardSelectionPolicy(KeyboardSelectionPolicy.ENABLED);

     // Open the first playlist by default.
     TreeNode rootNode = tree.getRootTreeNode();
     TreeNode firstPlaylist = rootNode.setChildOpen(0, true);
     firstPlaylist.setChildOpen(0, true);

     // Add the tree to the root layout panel.
     RootLayoutPanel.get().add(tree);
   }
 }
	/*
	* Copyright 2010 Google Inc.
	*
	* Licensed under the Apache License, Version 2.0 (the "License"); you may not
	* use this file except in compliance with the License. You may obtain a copy of
	* the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
	* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
	* License for the specific language governing permissions and limitations under
	* the License.
	*/
	package com.google.gwt.examples.cellview;

	import com.google.gwt.cell.client.AbstractCell;
	import com.google.gwt.cell.client.Cell;
	import com.google.gwt.cell.client.TextCell;
	import com.google.gwt.core.client.EntryPoint;
	import com.google.gwt.safehtml.shared.SafeHtmlBuilder;
	import com.google.gwt.user.cellview.client.CellTree;
	import com.google.gwt.user.cellview.client.HasKeyboardSelectionPolicy.KeyboardSelectionPolicy;
	import com.google.gwt.user.cellview.client.TreeNode;
	import com.google.gwt.user.client.ui.RootLayoutPanel;
	import com.google.gwt.view.client.ListDataProvider;
	import com.google.gwt.view.client.SingleSelectionModel;
	import com.google.gwt.view.client.TreeViewModel;

	import java.util.ArrayList;
	import java.util.List;

	/**
	* Example of {@link CellTree}. This example shows a Tree consisting of
	* composers and the compositions they created.
	*/
	public class CellTreeExample2 implements EntryPoint {

	/**
	* A list of songs.
	*/
	private static class Playlist {
	private final String name;
	private final List<String> songs = new ArrayList<String>();

	public Playlist(String name) {
	this.name = name;
	}

	/**
	* Add a song to the playlist.
	*
	* @param name the name of the song
	*/
	public void addSong(String name) {
	songs.add(name);
	}

	public String getName() {
	return name;
	}

	/**
	* Return the list of songs in the playlist.
	*/
	public List<String> getSongs() {
	return songs;
	}
	}

	/**
	* A composer of classical music.
	*/
	private static class Composer {
	private final String name;
	private final List<Playlist> playlists = new ArrayList<Playlist>();

	public Composer(String name) {
	this.name = name;
	}

	/**
	* Add a playlist to the composer.
	*
	* @param playlist the playlist to add
	*/
	public Playlist addPlaylist(Playlist playlist) {
	playlists.add(playlist);
	return playlist;
	}

	public String getName() {
	return name;
	}

	/**
	* Return the rockin' playlist for this composer.
	*/
	public List<Playlist> getPlaylists() {
	return playlists;
	}
	}

	/**
	* The model that defines the nodes in the tree.
	*/
	private static class CustomTreeModel implements TreeViewModel {

	private final List<Composer> composers;

	/**
	* This selection model is shared across all leaf nodes. A selection model
	* can also be shared across all nodes in the tree, or each set of child
	* nodes can have its own instance. This gives you flexibility to determine
	* how nodes are selected.
	*/
	private final SingleSelectionModel<String> selectionModel = new SingleSelectionModel<String>();

	public CustomTreeModel() {
	// Create a database of information.
	composers = new ArrayList<Composer>();

	// Add compositions by Beethoven.
	{
	Composer beethoven = new Composer("Beethoven");
	composers.add(beethoven);

	Playlist concertos = beethoven.addPlaylist(new Playlist("Concertos"));
	concertos.addSong("No. 1 - C");
	concertos.addSong("No. 2 - B-Flat Major");
	concertos.addSong("No. 3 - C Minor");
	concertos.addSong("No. 4 - G Major");
	concertos.addSong("No. 5 - E-Flat Major");

	Playlist quartets = beethoven.addPlaylist(new Playlist("Quartets"));
	quartets.addSong("Six String Quartets");
	quartets.addSong("Three String Quartets");
	quartets.addSong("Grosse Fugue for String Quartets");

	Playlist sonatas = beethoven.addPlaylist(new Playlist("Sonatas"));
	sonatas.addSong("Sonata in A Minor");
	sonatas.addSong("Sonata in F Major");

	Playlist symphonies = beethoven.addPlaylist(new Playlist("Symphonies"));
	symphonies.addSong("No. 2 - D Major");
	symphonies.addSong("No. 2 - D Major");
	symphonies.addSong("No. 3 - E-Flat Major");
	symphonies.addSong("No. 4 - B-Flat Major");
	symphonies.addSong("No. 5 - C Minor");
	symphonies.addSong("No. 6 - F Major");
	symphonies.addSong("No. 7 - A Major");
	symphonies.addSong("No. 8 - F Major");
	symphonies.addSong("No. 9 - D Minor");
	}

	// Add compositions by Brahms.
	{
	Composer brahms = new Composer("Brahms");
	composers.add(brahms);
	Playlist concertos = brahms.addPlaylist(new Playlist("Concertos"));
	concertos.addSong("Violin Concerto");
	concertos.addSong("Double Concerto - A Minor");
	concertos.addSong("Piano Concerto No. 1 - D Minor");
	concertos.addSong("Piano Concerto No. 2 - B-Flat Major");

	Playlist quartets = brahms.addPlaylist(new Playlist("Quartets"));
	quartets.addSong("Piano Quartet No. 1 - G Minor");
	quartets.addSong("Piano Quartet No. 2 - A Major");
	quartets.addSong("Piano Quartet No. 3 - C Minor");
	quartets.addSong("String Quartet No. 3 - B-Flat Minor");

	Playlist sonatas = brahms.addPlaylist(new Playlist("Sonatas"));
	sonatas.addSong("Two Sonatas for Clarinet - F Minor");
	sonatas.addSong("Two Sonatas for Clarinet - E-Flat Major");

	Playlist symphonies = brahms.addPlaylist(new Playlist("Symphonies"));
	symphonies.addSong("No. 1 - C Minor");
	symphonies.addSong("No. 2 - D Minor");
	symphonies.addSong("No. 3 - F Major");
	symphonies.addSong("No. 4 - E Minor");
	}

	// Add compositions by Mozart.
	{
	Composer mozart = new Composer("Mozart");
	composers.add(mozart);
	Playlist concertos = mozart.addPlaylist(new Playlist("Concertos"));
	concertos.addSong("Piano Concerto No. 12");
	concertos.addSong("Piano Concerto No. 17");
	concertos.addSong("Clarinet Concerto");
	concertos.addSong("Violin Concerto No. 5");
	concertos.addSong("Violin Concerto No. 4");
	}
	}

	/**
	* Get the {@link NodeInfo} that provides the children of the specified
	* value.
	*/
	public <T> NodeInfo<?> getNodeInfo(T value) {
	if (value == null) {
	// LEVEL 0.
	// We passed null as the root value. Return the composers.

	// Create a data provider that contains the list of composers.
	ListDataProvider<Composer> dataProvider = new ListDataProvider<CellTreeExample2.Composer>(
	composers);

	// Create a cell to display a composer.
	Cell<Composer> cell = new AbstractCell<Composer>() {
	@Override
	public void render(Context context, Composer value, SafeHtmlBuilder sb) {
	if (value != null) {
	sb.appendEscaped(value.getName());
	}
	}
	};

	// Return a node info that pairs the data provider and the cell.
	return new DefaultNodeInfo<Composer>(dataProvider, cell);
	} else if (value instanceof Composer) {
	// LEVEL 1.
	// We want the children of the composer. Return the playlists.
	ListDataProvider<Playlist> dataProvider = new ListDataProvider<Playlist>(
	((Composer) value).getPlaylists());
	Cell<Playlist> cell = new AbstractCell<Playlist>() {
	@Override
	public void render(Context context, Playlist value, SafeHtmlBuilder sb) {
	if (value != null) {
	sb.appendEscaped(value.getName());
	}
	}
	};
	return new DefaultNodeInfo<Playlist>(dataProvider, cell);
	} else if (value instanceof Playlist) {
	// LEVEL 2 - LEAF.
	// We want the children of the playlist. Return the songs.
	ListDataProvider<String> dataProvider = new ListDataProvider<String>(
	((Playlist) value).getSongs());

	// Use the shared selection model.
	return new DefaultNodeInfo<String>(dataProvider, new TextCell(),
	selectionModel, null);
	}

	return null;
	}

	/**
	* Check if the specified value represents a leaf node. Leaf nodes cannot be
	* opened.
	*/
	public boolean isLeaf(Object value) {
	// The leaf nodes are the songs, which are Strings.
	if (value instanceof String) {
	return true;
	}
	return false;
	}

	}

	public void onModuleLoad() {
	// Create a model for the tree.
	TreeViewModel model = new CustomTreeModel();

	/*
	* Create the tree using the model. We use <code>null</code> as the default
	* value of the root node. The default value will be passed to
	* CustomTreeModel#getNodeInfo();
	*/
	CellTree tree = new CellTree(model, null);
	tree.setKeyboardSelectionPolicy(KeyboardSelectionPolicy.ENABLED);

	// Open the first playlist by default.
	TreeNode rootNode = tree.getRootTreeNode();
	TreeNode firstPlaylist = rootNode.setChildOpen(0, true);
	firstPlaylist.setChildOpen(0, true);

	// Add the tree to the root layout panel.
	RootLayoutPanel.get().add(tree);
	}
	}